Fabrication Of Carbon Micro-Structures Using C-MEMS Technology

When pyrolysis with photoresist as the organic precursor combines thick film photolithography,they give birth to a novel method manufacturing carbon microstructures called"C-MEMS". It has easier and repeatable process, low cost, and structures derived from it could have smart designs. Carbon micro-structures fabricated through the process display high aspect ratio, excellent electronic and heat conductivity, and better mechanical properties. Besides, they are also bio-compatible and chemical inertia. We worked on C-MEMS theory, optimized process, fabricated carbon micro-electrode array with good properties, and developed the process to fabricate suspended carbon micro-structures. The contents of this thesis includes:It has been reviewed that the current research on C-MEMS and various applications of this technology. We analyzed the core processes of C-MEMS which are thick-film photolithography and photoresist pyrolysis. By doing so, we attached importance on the re-fabrication of photoresist micro-structures with high aspect ratio and prevention of deformation or delamination of the carbon structures through pyrolysis control.SU-8 2100 photoresist has been applied in this study, and carbon micro-post array with height of 100μm was obtained, the aspect-ratio of which could reach 2.5:1. And the SU-8 film after pyrolysis of 1000℃shows characteristics of glassy carbon, with thin film resistance of about 2.5Ω/□and the resistance of 1.56×10^-5Ω·m. The EDAX analysis of the pyrolyzed film shows that the atom composition of carbon is as high as 93.6%. Carbon microstructures made through this process could be applied to fields such as micro-batteries, electrochemical micro-sensor and bio-chip et al.Based on the pillar carbon micro electrode array, complex structures such as suspended carbon ribbon, carbon networks, and carbon fibers could be fabricated. These suspended structures offered new solution to the problem of electric connection in micro-electronic and bio-sensing.At last, several problems of C-MEMS research has been analyzed, such as"T-top", self-organized bunches and character collapse, and tried to bring forward solutions. In the mean time, delamination between the fabricated carbon micro-structures and substrate is the biggest obstacle to the application of C-MEMS technology. To solve the problem, surface processed Si substrate has been used and KOH immersion demonstrated its effect. In the mean time, micro-mechanical interlocking experiment has also been designed to improve adhesion.